Abstract: The possible kinds of symmetry for ordinary things in
3-dimensional space were classified more than a century ago, as were the
kinds of symmetry possible for repeating patterns in the plane and
3-space, but it’s only recently become clear how we should have found
them.

I’ll say how, and maybe discuss some of the other contents of the
forthcoming book written jointly with Heidi Burgiel and Chaim
Goodman-Strauss, which has the same title as this lecture.